Strand tension indicating device



H. R. THORNTON STRAND TENsIoN INDICATING DEVICE Filed July 1o, 1943.Ill-

July 4, 1944.

Patented July 4, 1944 STRAND TENSION INDICATING bavlca Horace R.Thornton, Baltimore, Md., assigner to Western Electric Company,Incorporated,- New York, N. Y., a corporation oi' New York ApplicationJuly 10, 1943, Serial No. 494,217

7 Claims. Y (Cl. 5'1'-59)k VThis invention relates to strandrtensionindicating devices and particularly to such devices for use in strandhandlingmachines of the general type disclosed in co-pending applicationSerial No. 452,027, led July 23, 1942, the device being associated withmeans :for stopping the operation of the machine when a given degree ofinequality of tension exists in the strands..

In the manufacture of electrical communication cable, for example, thetype produced in the above-referred-to type of machine, whereinVindividual conductors are twisted into pairs and the pairs are then`twisted into a cable, it is very necessary, in establishing uniformityin the in'- dividual pairs of conductors that the two twisted rpairs ofconductors should, at all times, travel under similar Yand constanttensions before being twisted together. Consequently, it is necessary,when inequality of tension develops between the twisted pairsofconductors, that it 'Y be immediately indicated and, upo'n agivendetailed description taken in conjunction with the accompanyingdrawing, in which Y 'Y `lig. 1 is a diagrammatic plan view of arstrandktwisting machine showing a strand tension indicating vdevice andassociatedrmeans for stopping the machine embodying. vthe featuresrofthe invention; and

Fig. 2 is an enlarged longitudinal-central section of the tensionindicating device and associated means shown rotated tion thereof inFig. 1. Y

In the drawing, an embodiment of theV inven- A"tion is illustrated asapplied to a strand twisting gree of inequality in such tensions'developing, y

that the machine be automatically stopped.

An object ofv this invention is to provide a simple and practicabledevice for indicating inequality of tensions between advancing strandsassociated therewith and cooperating with means for stopping ytheadvance of the strands when a givendegree of inequality vof tensionsexists in the strands. Y

In accordance with the above objects, the present invention, in theembodimentthereof, as applied to the above-referredto type of strandtwisting machine for forming electrical communication cables, comprisesa horizontally reciprocatory bar normally held in `a predeterminedposition relative to and extending'trans versely to the advancingtwisted pairs of conductors by spring means, the bar carrying a sheaveat each end over which the twisted pairs of conductors travel andanindicator movable with the bar and cooperating with indicia forindicating any movement'of the bar against the action of the springmeans andthus that a condition of unequal tension has'developed in thepairs of twisted conductors advancing over.A the sheaves, and alsowhichpair has thevgreater tension. Associated with the indicator are elec-Atrical limit switches effective, upon a given Aclegree of inequality oftensions, stop the machine. y

Other objects and advantages of the invention will more fully appearfrom the following demachine ofthe general type disclosed in thereferred-to co-pending application, Serial No. 452,027, led July 23,1942, t0 which reference maybe had for a more detailed disclosure ofsuch machine and its operation. lnFig. 1, only such parts of thetwisting machine are shown in broken lines as are necessary to afullfunderstanding'of one use of the device of this invention,indicated'ingeneral at 5.

y The parts of the twisting machine which are shown in Fig. 1, aremounted on a base 6 having vertical housings 1. Journalled on andbetween the two left-hand housings 'I are two flier units, indicated ingeneral at l0 and II, each having two'supply reels` I2,'onlyone ofwhichis shown,

arrangedrside by side on a commonaxis. In

the operation of the machine, Vthe ilier units Illy and II are actuatedto twist conductors I3'withdrawnfrom the reels I2 included in each :ier

unit into pairs, the conductors receiving one twist per revolution ,oftheir respective iliers upon approaching their sheaves VI4 and anothertwist after passing over sheaves I5 and I6 of their flier units. Theiiier units I0 and II, are driven in like directions rat speedssuliicientto place lovertwists inthe pairsvof conductors I3 to offsetthe tendency of a ier unit at the right hand end of the machine fromuntwisting the pairs when these pairsare twisted together in an optoautomatically posite direction from that of their original twist.V

Upon leaving thelflier` units I ilv and II, the

Vconductors vI3 arein twisted pairs, indicated at l JB, which convergeYand pass through a hollow shaft I9 to a flier unit, indicated in generalatA 20, in which a capstanZI is disposed, the flier unit 20 beingjournalledv on and between [the right hand vertical housingsl l. rThecapstan 2| is rotated counterclockwise, as, seen in Fig. 1, tocauseadvancernent of the conductors `rI3ffrom their respective supplyreels I 2V, through the ier units I(l and II, andthe pairs I 8` throughthe V from.` the posiv -twists to form a cable, indicated at 23, due tothe flier unit 20 being driven in a direction opposite l that of thefiler units I and II. Thereafter,

the cable'23 passes around the capstan 2| to effect a'pulling connectionbetween the capstan and the cable, after which the cable is vfed oversheaves 24 and 25 to a takeup reel26. lA common power means, such as amotor 28, is provided for driving, through suitable interconnectingmeans, the various parts of the machine, although separate speedreducing units 29 and 30 may be employed for the left and right handends, respectively, of the machine.

With this general understanding of the machine and what it accomplishesand realizing the necessity of uniformity in the individual twistedpairs I6 of conductors I3 and that they should travel at all times undersimilar and constant tensions, attention is now directed to the strandtension indicating device of this invention and its associated means forstopping the machine when a given degree of inequality of tension existsin vthetwisted pairs of conductors. Secured to and extendinghorizontally from theinner vertical housing 1 at the left hand endV ofthe machine is a support 32 having integral vertical standards, 33interconnected at their upper ends by a sleeve-like portion 34 withheads 35 at opposite ends. Extending freely through Vthe bore of thesleeve-like portion 34 is a reciprocatory bar or rod 36. Fixed to therod 36 intermediate its ends is an indicator or pointer 40, which, atone end is associated with indicia 4I marked on a plate 42 carried on,the support 32, the opposite end of the indicator being arranged Y toactuate one of two plungers 43 of normally i closed limit switches 44carried on the support 32 upon the rod 36 being moved longitudinally apredetermined distance in either direction. As shown in Fig. 1, thelimit switches 44 are connected in'parallel in the Vcircuit to the motor28. Opposite slots 41 in the sleeve-like portion 34 permit longitudinalmovement of the rod 36 with made in the adjustable means provided in thereferred-to reel supporting mechanisms.

In the use of the device 5 of this invention as applied to theabove-noted strand twisting machine and assuming that the twistedconductor pairs lI8 are advancing convergently from the iiier 'units I0and II to a common point under i equal tensions over the sheaves 52 ofthe tension indicating device, the rod 36 will remain in its centralposition and the indicator 40 will, consequently, register with thecenter mark 48 of the indicia 4|, thus indicating that a condition ofequal tension exists between the pairs I8. Whenever. a greater `tensiondevelops in one of the pairs I8, due to any cause, the rod 36 will beshifted in the direction of the pair having the greater tension untilboth pairs have reached equal tension. The resultant movement of theindicator 40, moving with the rod 36, away from the mark 48, immediatelyindicates that a condition of unequal tension from, that desired hasdeveloped, and also which pair has developed the greater tension.Suitable adjustment is then y made through one or the other of thepreviously the attached indicator 40 and the arrangement is such thatthe rod is prevented from rotating. The lrod 36 is'normally yieldablymaintained in a central position in the sleeve-like portion 34 f withthe indicator 4o registered with a center mark 48 of the indicia 4I bymeans of similar coiled compression springs 49 surrounding the rod atopposite sides of the indicator, the opposite ends of the springsvabutting adjacent sides of the. pointer and adjustable nuts 50 threadedinto the heads 35, the Vrod 36 having a sliding iit in bores 5I of thenuts 50. The nuts 50 provide meansl for adjusting the compression of thesprings 48 and also to balance the indicator 40. A sheave '52 isjournalled upon each end of the rod 36 and the twisted pairs I8 ofconductors I3 are guided iii their advance from the flier units I0 and II over the sheaves.

scribed and disclosed in the above-referred-to co-pending application,for causing the conductors I3 to travel from the reels I2 of the flierunits l0 and II vand'thereafter in the form of twisted pairs I8 underlike and constant tensions. At times, due to various causes, the twopairs I8 of conductors I3 may not be under the same tension and, in suchcase, suitable adjustment is referred-to means associated with the reelSupporting mechanisms to again cause -thev desired degree of equality oftension betweentl-ie twisted conductor pairs I8.v Whena given ydegreefof inequality of tension develops betvl/'een the'jpairs I8, theopposite end of the'indic'ato'r 4I)y will lengage and actuate one or theother of the plung- -ers 43 of the normally'closed limit'switches 44 andthereby open the power circuit to the motor 28 to cause an immediatestoppage ofthe twistlng machine. l f` Fromthe foregoing description; itwill'be ap- Y parent that a simple and practicable strand tensionindicating device is provided for "use in strand twisting machines,vwhich is effective to provide a visual indication of Vany inequality oftension between advancing strands or variations from desired differenttensions between such strands, if such is the case. Also, in the case ofsuch equalities or variations exceeding a predetermined degree, meanscooperating with the tension indicating device is eiective to cause animmediate stoppage of the machine. Y

It will be understood that the embodiment herein described is merelyillustrative of the invention and one application thereof and thatmodifications can be made and'it is capable oi other applications.

' What is claimed is:

, 1. A tension indicating devicefor a plurality of spaced strands duringhandling in a strand handling machine comprising a reciprocably mountedmember, yieldable means for maintaining said member in a predeterminedposition, opposite portions of said member adapted to be engaged by saidstrands, and means including an indicator movable with said member forindicating movement thereof against the action of said yieldable meanswhen undesired tensions exist in the strands.

2. A tension indicating device for strands being advanced in a strandhandling machine comprising a reciprocably mounted member, yieldablemeans for maintaining said member in a predeterminedposition, rollerscarried upon opposite ends of said member over which the strandsadvance, and means including an indicator movable strands in a strandhandling machine comprising an apertured support, a reciprocable membermovable longitudinally therein, said member having an enlargementintermediate its ends, apertured means at opposite ends of said supportfor guiding said reciprocable member, coiled compression springssurrounding said member at each side of and abutting at their adjacentends opposite faces of said enlargement, the opposite ends of saidsprings abutting said apertured means, opposite ends of said memberadapted to be engaged by said strands,4 and means including an indicatorcarried by and intermediate said faces of said enlargement forindicating movement thereof against the action of said springs whenundesired tensions exist in the strands.

4. A device for indicating tension in advancing strands in a strandhandling machine which includes power actuating means thereforcomprising a reciprocably mounted member, lyieldable means formaintaining said member in a predetermined position, opposite portionsof said member adapted to be engaged by said strands, means including anindicator movable with said member for indicating movement thereofagainst the action of said yieldable means when undesired tensions existin the strands, and means responsive to la predetermined movement ofsaid indicator when a given degree of undesired tensions exists in thestrands to interrupt the operation of the power actuating means of themachine.

5. A tension indicating device for a machine in which spaced strands areadvanced convergently to a common point comprising a reciprocablymounted member movable transversely of the direction of advance of thestrands, means including yieldable elements eiective for maintainingsaid member in a predetermined position, opposite portions of saidmember adapted to be engaged by said advancing strands, and meansincluding an indicator movable with said member for indicating movementthereof against the action of said yieldable elements when unequaltensions exist in the strands.

6. A tension indicating device for a machine in which spaced strands arefed convergently to a common point comprising yieldably mounted meansengaging the spaced strands and movable in opposite directionstransversely of the direction of advance and in accordance with thedifferential of the tensions in the strands, and

means cooperating with said strand engaging chine.

HORACE R. THORNTON.

